On Friday we released version 1.5 of the Rancher container management platform. The enhancements in this release are designed to help ensure enterprise- as well as production-readiness. Additional webhooks improve Rancher extensibility and enable you to optimize overall infrastructure utilization. New API, networking and container scheduling policies provide fine-grained control of the container environment. Additional enhancements include metadata performance improvements and conditional logic support for catalog templates.
Additional webhooks drivers
With Rancher 1.4, we added webhooks, with an initial driver to handle scaling. The key to implementing webhooks is the ‘receiver’, which enables you to register a webhook and provides a URL to trigger an action inside Rancher software. Thanks to the community feedback we received, in Rancher 1.5 we were able to extend the Rancher webhooks implementation to include two new drivers:
- Host scaling webhook, which scales hosts up or down
- DockerHub service upgrade webhook configured for Dockerhub image updates and used to update services in Rancher using that image
As always, we welcome additional feedback on these and other capabilities via the forums.
Enhanced policy controls
Rancher 1.5 delivers enhanced policy controls, including the ability to intercept all API requests. In addition, pre/post filter logic can now be added to each request, providing administrators with greater flexibility to define and control API access. Fine grained API policy management can be enabled to modify the API request as well as the response payload both to and from Rancher. Two additional networking policies have been added, which can be configured for each environment. The first enables you to allow or deny communication outside of a service. By default, Rancher is setup to allow communication between all services within an environment. If configured to deny communication, however, the containers will unable to communicate with containers outside of a service. The second policy enables link support so that services or stacks which are configured to deny communication can be given permission to communicate by using either a Docker link or selector labels. Additional policy controls are also now available for container scheduling. Rancher 1.5 supports the ability to add tags which restrict container scheduling to specific hosts. Placement of containers is determined by pre-specified labels, providing improved control over how each host is utilized.
Metadata performance improvements
The Rancher metadata service has been improved by caching metadata information. This reduces database thrashing as well as the footprint of the metadata passed on to each metadata service. Since so many services rely on metadata, depending on your implementation, you should see an overall improvement in Rancher performance. You will also see improvements when you launch large volumes of containers at the same time or when adding a new container after multiple containers are already running.
Conditional logic support for catalog templates
Rancher container management now supports the ability to use conditional logic by leveraging the Go template system. Using conditional logic combined with variable interpolation will provide greater flexibility to generate more dynamic catalog templates. More information about Rancher 1.5 container management can be found in the release notes*. For production use, we recommend waiting for the stable release, which will be available shortly.